Study of the antioxidant power of brandies and vinegars derived ...

718 A.M. Alonso et al. / Food Research International 37 (2004) 715–721
[trolox] eq (mM)
3
2
1
0
R = 0.9175
0 1 2 3 4
GAE (mg/L) /100
Fig. 3. Correlation line between total polyphenolic index (GAE) and
antioxidant power ([Trolox]eq) of brandies.
[trolox] eq (mM)
6
4
2
R = 0.9201
10
8
6
4
2
0
V1 V2 V3 V4 V5 V1-W V2-W V3-W V4-W V5-W V6-W V7-W
0
0 2 4 6 8
GAE (mg/L) /100
Fig. 4. Correlation line between total polyphenolic index (GAE) and
antioxidant power ([Trolox]eq) of vinegars.
is not surprising that wood contact does not influence the
polyphenols content of vinegar because for this type of
product, the main source of polyphenols is the base-wine.
So, the differences in GAE (200–1000 mg/L, Fig. 2) found
among vinegar samples, are probably due to the different
wines of origin used by each company.
These findings could indicate that, in general, the
antioxidant power in brandies and vinegars is determined
or highly influenced by their polyphenolic
content.
In order to discover if a particular compound has
more influence than any other in determining the anti-
5
10
GAE(mg/L) /100
[trolox]eq (mM)
Fig. 2. Total polyphenolic index (GAE) and antioxidant power ([Trolox]eq) of vinegars.
oxidant power, a new correlation analysis was made
between the measures of AP and the results of the
chromatography (Tables 3 and 4).
In the case of the brandies, most of the compounds
presented a low correlation (Table 3). Some compounds
exhibited a good correlation for SB (sculetin, followed
by vanillic acid, coniferylaldehyde and scopoletin) and
for SRB (coniferylaldehyde, followed by vanillic and
syringic acids). In general, for all the types of brandies,
coniferylaldehyde was significant.
For the particular case of vinegars, the correlation
analysis could just be done for compounds identified in
more than two samples. In general, it was found that
most of polyphenols identified presented a high correlation
with the AP measured (Table 4). For the vinegars
without aging, gallic acid was especially important; this
polyphenol was also one of the most abundant in the
samples. For the vinegars aged in wood, cis-p-coumaric,
ferulic, i-ferulic, and syringic acids together with vanillin
and p-hydroxy benzaldehyde exhibited high correlation
values.
In relation to the polyphenolic content found in
the samples studied, the values obtained are shown in
Tables 5 and 6. For the three types of brandy, the same
compounds were found, although in lower quantity in
the Solera brandies. The most important were vanillin
and siringic acid, followed by sculetin and vanillic acid.
This finding is in agreement with the wood origin of the
polyphenols commented before.
In the case of the vinegars, the most abundant compounds,
in general, were gallic acid and tyrosol. For the
vinegars in process of production (not aged), caftaric
acid, the major phenolic compound found in recently
prepared musts, is also significant. Those that were aged
in wood show a high content of catechin. Other authors
(Garcıa-Parrilla, Heredia, & Troncoso, 1999) have
found that gallic acid is concentrated during aging,
which is confirmed in this study. Previous research
works (Carrero, Barroso, & Perez-Bustamante, 1999;